Prescription opioid (PO) use, including non-medical PO (NMPO) use, has become alarmingly common in the US. This has major implications for people living with HIV (PLHIV), for whom chronic pain, which is often undiagnosed or incompletely relieved, and substance use are common. Self-management of pain symptoms with NMPOs as well as marijuana has been reported in the general population, and some studies found associations between higher pain interference and NMPO use. The severity of NMPO use among PLHIV, however, is not well described. It has been reported to be 2-3 times higher than in the general population, but these few studies relied on outdated data or non-representative. Furthermore there is a paucity of research on the relationship between chronic pain and substance use (NMPO use, specifically) in PLHIV despite the well-documented, higher prevalence of these conditions compared to the general population. The objective of this proposal is to characterize NMPO use among PLHIV and explore the intersection of NMPO use, chronic pain, and marijuana use in a large HIV clinic in the Southeastern US where the joint epidemics of HIV and PO use are acutely felt. We propose a cross-sectional survey of 500 PLHIV receiving care at the Vanderbilt Comprehensive HIV Care Clinic (VCCC) to achieve the following aims: Aim 1 - To characterize NMPO use in our generalized HIV patient population and assess its association with uncontrolled or insufficiently relieved chronic pain. Aim 2 - To determine the associations between marijuana use, uncontrolled or insufficiently relieved chronic pain, and NMPO use. Data will be collected from multiple sources including a comprehensive survey on pain and substance use, urine drug screen, and clinical data from electronic medical records. NMPO use will be described in detail, including source and existing or history of prescribed opioids, and further compared to non-users. Multivariable logistic regression analysis will explore Aims 1 and 2 while controlling for important confounders including socio-demographics, depression, and anxiety. We hypothesize that higher levels of insufficiently relieved pain will be associated with higher NMPO (Aim 1) and marijuana (Aim 2) use. We hypothesize that the marijuana-NMPO use association (Aim 2) will differ depending on chronic pain status, reflecting self-management of pain among those reporting pain, and recreational, polysubstance use among those not reporting pain. In a population with high substance use, the proposed study explores NMPO use through the lens of uncontrolled or insufficiently relieved pain, which may represent a different behavior from other illicit substance use. Findings will provide insight into how to better manage pain clinically, while avoiding known risks of PO use such as misuse, dependence, and overdose. While much research will need to be done on this understudied issue among PLHIV, the proposed study lays the foundation for this important work.